1. Field of the Invention
This invention relates to dental implants, and in particular to an apparatus and method to remove a dental implant.
2. Background of the Invention
Implants in a patient's jaw bone are routinely used in the dentistry arts to anchor individual prosthetic teeth as well as bridges containing a number of prosthetic teeth. As may be observed in FIG. 1, a side cross-sectional view of implant 2, an appropriate aperture is made in bone 4, implant 2 inserted, and then over time bone 4 grows over implant 2, thus securely anchoring it in place.
Referring now also to FIG. 2, a top view of implant 2 in bone 4, implant 2 typically comprises implant indexing means 6, and an implant connector 8. After implant 2 is firmly anchored in bone 4, a prosthesis is attached to it. Implant indexing means 6 is sized to mate with a matching prosthesis indexing means, in order to prevent rotating of the prosthesis relative to implant 2 after the prosthesis is installed on implant 2. While in FIGS. 1 and 2 implant indexing means 6 was an external hex, 2 implant indexing means 6 may be any appropriate shape, including but not limited to any external polygonal or other shape, any internal polygon or other shape, etc.
In FIGS. 1 and 2, implant connector 8 is a threaded bore 8, which may be used to attach a prosthesis to implant 2 by means of a threaded fastener sized to mate with the threaded bore which is implant connector 8.
On occasion it becomes necessary to remove an implant 2 which was previously 7 installed in bone 4. A trephine burr, such as trephine burr 10 depicted in FIG. 3, is used to accomplish this task. The trephine burr drills around the outside edge of implant 2 to a depth substantially equal to the depth of implant 2 within bone 4. Trephine burr 10 is then withdrawn and implant 2 lifted out of bone 4.
One problem associated with current trephine drilling procedures connected with implant extraction is the difficulty of maintaining trephine burr 10 parallel with implant 2, to prevent drilling into implant 2 with trephine burr 10. The result would be small chips of implant 2 left within bone 4. As most implants 2 are made of metal, these left-behind chips severely reduce visibility when subsequent X-rays are taken of the area. Given the importance of X-rays in the dental sciences as a diagnostic and evaluation tool, this is a serious consequence, indeed. Thus, it would be desirable to provide a means to hold trephine burr 10 correctly aligned with implant 2 during the implant removal operation.
A relatively recent development in dental implant technology involves mounting an abutment to a dental implant, and then mounting a prosthesis to the abutment. This configuration is depicted in FIGS. 12 and 14. In FIG. 12 abutment 12 is ready to be installed on implant 2, which installation is accomplished by mating abutment implant connector 14 with implant connector 8 as indicated by arrows 20 and 22 in FIG. 12. While FIGS. 12–16 illustrate abutment implant connector 14 as a threaded stud and implant connector 8 as a threaded bore, either may be any appropriate connector—for instance, abutment implant connector 14 could be a threaded bore and implant connector 8 could be a threaded stud, or abutment implant connector 14 and implant connector 8 may be any other appropriate pair of mating connectors.
When an abutment 12 attached to an implant 2 is to be removed from bone 4 in which it resides, an important problem associated with current trephine drilling procedures connected with this extraction is the difficulty of maintaining trephine burr 10 parallel with abutment 12 and implant 2, to prevent drilling into abutment 12 and/or implant 2 with trephine burr 10. The result would be small chips of abutment 12 and/or implant 2 left within bone 4. Where abutment 12 and/or implants 2 are made of metal, these left-behind chips severely reduce visibility when subsequent X-rays are taken of the area. Given the importance of X-rays in the dental sciences as a diagnostic and evaluation tool, this is a serious consequence. Thus, it would be desirable to provide a means to hold trephine burr 10 correctly aligned with abutment 12 and implant 2 during the implant removal operation.